Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Open Menu / mm / gup_benchmark.c
Loading...
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/ktime.h>
#include <linux/debugfs.h>

#define GUP_FAST_BENCHMARK	_IOWR('g', 1, struct gup_benchmark)

struct gup_benchmark {
	__u64 delta_usec;
	__u64 addr;
	__u64 size;
	__u32 nr_pages_per_call;
	__u32 flags;
};

static int __gup_benchmark_ioctl(unsigned int cmd,
		struct gup_benchmark *gup)
{
	ktime_t start_time, end_time;
	unsigned long i, nr, nr_pages, addr, next;
	struct page **pages;

	nr_pages = gup->size / PAGE_SIZE;
	pages = kvcalloc(nr_pages, sizeof(void *), GFP_KERNEL);
	if (!pages)
		return -ENOMEM;

	i = 0;
	nr = gup->nr_pages_per_call;
	start_time = ktime_get();
	for (addr = gup->addr; addr < gup->addr + gup->size; addr = next) {
		if (nr != gup->nr_pages_per_call)
			break;

		next = addr + nr * PAGE_SIZE;
		if (next > gup->addr + gup->size) {
			next = gup->addr + gup->size;
			nr = (next - addr) / PAGE_SIZE;
		}

		nr = get_user_pages_fast(addr, nr, gup->flags & 1, pages + i);
		if (nr <= 0)
			break;
		i += nr;
	}
	end_time = ktime_get();

	gup->delta_usec = ktime_us_delta(end_time, start_time);
	gup->size = addr - gup->addr;

	for (i = 0; i < nr_pages; i++) {
		if (!pages[i])
			break;
		put_page(pages[i]);
	}

	kvfree(pages);
	return 0;
}

static long gup_benchmark_ioctl(struct file *filep, unsigned int cmd,
		unsigned long arg)
{
	struct gup_benchmark gup;
	int ret;

	if (cmd != GUP_FAST_BENCHMARK)
		return -EINVAL;

	if (copy_from_user(&gup, (void __user *)arg, sizeof(gup)))
		return -EFAULT;

	ret = __gup_benchmark_ioctl(cmd, &gup);
	if (ret)
		return ret;

	if (copy_to_user((void __user *)arg, &gup, sizeof(gup)))
		return -EFAULT;

	return 0;
}

static const struct file_operations gup_benchmark_fops = {
	.open = nonseekable_open,
	.unlocked_ioctl = gup_benchmark_ioctl,
};

static int gup_benchmark_init(void)
{
	void *ret;

	ret = debugfs_create_file_unsafe("gup_benchmark", 0600, NULL, NULL,
			&gup_benchmark_fops);
	if (!ret)
		pr_warn("Failed to create gup_benchmark in debugfs");

	return 0;
}

late_initcall(gup_benchmark_init);